From 8c9952b26b2be25311706082598e5e176eb92748 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date: Mon, 3 Nov 2014 16:09:58 -0500
Subject: [PATCH] HID: logitech-hidpp: fix negated returns
Reported by Dan Carpenter:
drivers/hid/hid-logitech-hidpp.c:359 hidpp_root_get_protocol_version() warn: should this return really be negated?
drivers/hid/hid-logitech-hidpp.c:398 hidpp_devicenametype_get_count() warn: should this return really be negated?
drivers/hid/hid-logitech-hidpp.c:417 hidpp_devicenametype_get_device_name() warn: should this return really be negated?
drivers/hid/hid-logitech-hidpp.c:524 hidpp_touchpad_get_raw_info() warn: should this return really be negated?
The problem lies in hidpp_send_message_sync() which can return 2 types of
errors depending of their sign. Adding a comment there to clarify what is
happening.
To solve that, print an error in case of a protocol problem, and raise
-EPROTO instead.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
drivers/hid/hid-logitech-hidpp.c | 36 ++++++++++++++++++++++++++++----
1 file changed, 32 insertions(+), 4 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 8d2d54b527b0f..61f9e75c45d20 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -151,6 +151,14 @@ static int __hidpp_send_report(struct hid_device *hdev,
return ret == fields_count ? 0 : -1;
}
+/**
+ * hidpp_send_message_sync() returns 0 in case of success, and something else
+ * in case of a failure.
+ * - If ' something else' is positive, that means that an error has been raised
+ * by the protocol itself.
+ * - If ' something else' is negative, that means that we had a classic error
+ * (-ENOMEM, -EPIPE, etc...)
+ */
static int hidpp_send_message_sync(struct hidpp_device *hidpp,
struct hidpp_report *message,
struct hidpp_report *response)
@@ -359,8 +367,13 @@ static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp)
return 0;
}
+ if (ret > 0) {
+ hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
+ __func__, ret);
+ return -EPROTO;
+ }
if (ret)
- return -ret;
+ return ret;
hidpp->protocol_major = response.fap.params[0];
hidpp->protocol_minor = response.fap.params[1];
@@ -398,8 +411,13 @@ static int hidpp_devicenametype_get_count(struct hidpp_device *hidpp,
ret = hidpp_send_fap_command_sync(hidpp, feature_index,
CMD_GET_DEVICE_NAME_TYPE_GET_COUNT, NULL, 0, &response);
+ if (ret > 0) {
+ hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
+ __func__, ret);
+ return -EPROTO;
+ }
if (ret)
- return -ret;
+ return ret;
*nameLength = response.fap.params[0];
@@ -417,8 +435,13 @@ static int hidpp_devicenametype_get_device_name(struct hidpp_device *hidpp,
CMD_GET_DEVICE_NAME_TYPE_GET_DEVICE_NAME, &char_index, 1,
&response);
+ if (ret > 0) {
+ hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
+ __func__, ret);
+ return -EPROTO;
+ }
if (ret)
- return -ret;
+ return ret;
if (response.report_id == REPORT_ID_HIDPP_LONG)
count = HIDPP_REPORT_LONG_LENGTH - 4;
@@ -524,8 +547,13 @@ static int hidpp_touchpad_get_raw_info(struct hidpp_device *hidpp,
ret = hidpp_send_fap_command_sync(hidpp, feature_index,
CMD_TOUCHPAD_GET_RAW_INFO, NULL, 0, &response);
+ if (ret > 0) {
+ hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
+ __func__, ret);
+ return -EPROTO;
+ }
if (ret)
- return -ret;
+ return ret;
raw_info->x_size = get_unaligned_be16(¶ms[0]);
raw_info->y_size = get_unaligned_be16(¶ms[2]);
--
2.30.2